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This is a 4.070 X 3.622 377 ci built on a slightly damaged block of a front end collision 5th gen Camaro.
it’s been torque plate honed .005 over.
Mahle coated flat top pistons, 2cc dome 1.0, 1.0, 2.0mm rings. 4032 alloy hard anodized. .003 PTW clearance. Pistons out of the hole .009”
Scat I beam 6.125” rods 605 grams 7/16” ARP bolts, hollow dowel locators. (Better than stock rods in many ways)
Stock stroke OEM crank, micro polished
all the rod journals measured less than 2.100” by a few 10ths. 2.0996-2.0997.
Cammotion cam 227-237@.050 112 LSA .621- .614” lift about 8* overlap. Ordered with 112 vs 113 otherwise it’s a Titan3
Manton 7.185” .120 wall 11/32 pushrods.
Comp Cams link bar regular travel lifters, no trays. Unable to get Johnson’s at the time of this build because of their shutdown.
Texas speed roller tip steel rockers 1.72 ratio.
CamMotion .660 spring kit. Using .030” shims vs .060” locators. Spring height is 1.810 135lbs vs 148 closed.
853 heads Hand ported during shelter in place, 821 Hollow stem intakes 89grams vs 112gm truck valves.
Im excited to see what these heads can do for this motor, they have excellent mid lift flow numbers .3, .4, .5 and satisfactory peak lift number.
Fast LSXR 102 with mild port work done to the runner openings and a little work done to the base exits into the ports.
Nick Williams 102 TB stock 42lb LS3/LS7 injectors, 340lph In-Tank pump. LS2/LS3 coils, Taylor 10.4mm 40 ohm wires. NGK TR6s .040”
indexed down and toward exhaust, may not help but it couldn’t hurt it.
Holley 302-1 oil pan, Holley accessory pan baffle with trap doors, Performance improved crank scraper and windage tray.
Holley Terminator x engine management.
The goal here is 530 rwhp through a TH350
and an 8.8 rear axle, 3.55 ratio.
The cam is 112 + 2.5, it ended up at 109 so it’s maybe a 1/2* advanced. The crank is an OEM with 1 key way so the damper was pinned to the crank as a precaution. I had one spin on a motor and it effed up the snout.
Heads were milled .028” to 66.5-67cc, static compression to be approx 11.6:1, seems you have to use a domed piston to get into mid to high 11plus if you’re using LS3 heads. I’m weary of milling heads more than .030”
This motor is slightly lighter than the Gen4 based 347 that came out of this car, It’s using all the peripheral accessories of the 347 except the intake, throttle body and oil pan, Holley 302-1 vs C6 pan. The windage tray is aluminum here,
Nice build. Very detailed!
I did the same stuff inside my Fast intake. They are pretty cool to take apart. And easy to port match when you can set the base on and be able to mark where to grind.
Nice work on the “Covid” heads. 😊
I used a similar Mahle Piston set, but minus the dome as I’m Cathredral port. Nice parts and very reasonable cost.
Nice build. Very detailed!
I did the same stuff inside my Fast intake. They are pretty cool to take apart. And easy to port match when you can set the base on and be able to mark where to grind.
Nice work on the “Covid” heads. 😊
I used a similar Mahle Piston set, but minus the dome as I’m Cathredral port. Nice parts and very reasonable cost.
How long before it runs? And what’s it going in?
Ron
Thank you Ron. Right now I’m juggling 3 projects, 2 I’m trying get running, this LS3 and a 416 running, lots of little details to work out. Dome pistons will get the compression I’m looking for (11.6) nearly a whole point over an LS3. A cam grinder that used to be on this site (Martin)told me to leave nothing on the table when it comes to compression, “ make it as high as you can stand it) I did 11.6 on a 347 without issues.
Thank you Ron. Right now I’m juggling 3 projects, 2 I’m trying get running, this LS3 and a 416 running, lots of little details to work out. Dome pistons will get the compression I’m looking for (11.6) nearly a hole point over an LS3. A cam grinder that used to be on this site (Martin)told me to leave nothing on table when it comes to compression, “ make it as high as you can stand it) I did 11.6 on a 347 without issues.
With the little AFR heads at 60cc I measured right at 11.5:1. Actually CC’d everything.
Martin did the cam in my Turbo 5.3. Good guy.
Yes, thank you. Bortous, I know you’re down on req port heads for various reasons but I think theses will wok well for a few reasons: I didn’t make them big at all, I left them about what the intake runner size cross section is as cast, I just removed the lumps and bumps, blended the bowls and streamlined the guide bosses and that boosted the flow numbers at every level. I’m sure GM engineers knew what they were doing when opted for a 260cc rec port head for their 376.
Yes, thank you. Bortous, I know you’re down on req port heads for various reasons but I think theses will wok well for a few reasons: I didn’t make them big at all, I left them about what the intake runner size cross section is as cast, I just removed the lumps and bumps, blended the bowls and streamlined the guide bosses and that boosted the flow numbers at every level. I’m sure GM engineers knew what they were doing when opted for a 260cc rec port head for their 376.
You are right on my thoughts about LS3 style heads.
After being dissatisfied for so many years with these on my old engine I will never use them again.
Especially a GM version. Even modified I still wouldn't use them. Even if I changed my mind, I would only use them on a bore size of 4.125 or larger because even on an LS3 bore size, there is still some valve shrouding.
Mine were done by a hand porter years ago and I suspect it's this guy who didn't do a good job. Nothing was blended etc. Mainly the exhaust port was just hogged out.
I found old threads around the forums and one from Mamo actually which was really informative which explains all the downsides of this GM head.
This is not the thread to go into detail on this.
It's good you are trying to keep the intake port close to stock as possible. You don't want to hog it out too much.
Regardless of my thoughts about these heads I can still appreciate what you are doing with the engine.
The flow numbers on the intake side you got from the heads are good also.
You are right on my thoughts about LS3 style heads.
After being dissatisfied for so many years with these on my old engine I will never use them again.
Especially a GM version. Even modified I still wouldn't use them. Even if I changed my mind, I would only use them on a bore size of 4.125 or larger because even on an LS3 bore size, there is still some valve shrouding.
Mine were done by a hand porter years ago and I suspect it's this guy who didn't do a good job. Nothing was blended etc. Mainly the exhaust port was just hogged out.
I found old threads around the forums and one from Mamo actually which was really informative which explains all the downsides of this GM head.
This is not the thread to go into detail on this.
It's good you are trying to keep the intake port close to stock as possible. You don't want to hog it out too much.
Regardless of my thoughts about these heads I can still appreciate what you are doing with the engine.
The flow numbers on the intake side you got from the heads are good also.
Bort, if they prove to be a disappointment I’ll be shopping for some good C port heads. I’m optimistic with the car only weighing 2800 or less, the Fast 102s longer torque friendly runners, long headers and the not too big camshaft all of which will could lend itself to good drivability.
Bort, if they prove to be a disappointment I’ll be shopping for some good C port heads. I’m optimistic with the car only weighing 2800 or less, the Fast 102s longer torque friendly runners, long headers and the not too big camshaft all of which will could lend itself to good drivability.
I think they will do fine.
Your car is light and the intake you are using is good for torque production.
If you did want to take it up to the next level a set of AFR or trickflows would certainly do the trick.
I'm curious to see what you think of it after it's all completed.
10-09-2020, 11:42 AM
377 build 
